US1588077A - Flotation machine - Google Patents

Description

E. w. WILKINSON 'r Al.

FLoTATIoN MACHINE Filed Oct. 22, 1920 4 Sheets-Sheet 1 l ZZ ZZ A /f :P\ lI :I /fll :x VI I: l; :l ,52-1.1

' ICI BWM? y MM 9c Mal/f ATTORNEYS .June 8 1926. 1,588,077

E. w. WILKINSON 'E T AL FLoTATIoN MACHINE A Filed om. 22. 1920 4 sheets-sheet g j v i NZENTOR ATTORNEYS June 8 1926.

. E. w. wlLKlNsoN ET AL FLOTATION MACHINE Filed Oct. 22, 1920 `-4 Sheets-Sheet 5 A TTR/VEYS -June 8 1926. 1,588,077

E. w. WILKINSON Er AL FLoTATIoN MACHINE Filed oct. 22. -1920 4 sheets-sheet 4 M A rra/mfr Patented J une 8, 1926.

i UN'l'rieiD srATEs r ,1.588.011 P'fri-:ufueol-FIce.v

.'E'I'I'IOIWIy WBAY WILKINSON, Ol' SAN FRANCISCO, AND JOHN W. LITTLEFORD, OF ALA- MEDA, CALIFORNIA, ASSIGNORS T MINERALS SEPARATION NORTH AMERICAN CORPORATION, 0F NEW YOBK, N; Y., A CORPORATION 0F MARYLAND.

appuuon mea october 22, raso. serial' up. 418,707. y

l This invention relates to improvements lin apparatus for the concentration of ores or other materials andv is herein disclosed.` as applied to the froth-flotation separation process. In this processthe materials to be. separated are subjected to aeratlon 1n a liquid medium in the resence of a frothmg V se aration or differential froth-flotation.

he apparatus embodying this invention may be employed in the treatment of a large/ -variety of materials to effect a separation of certain 4components of said materials from other components thereof. Suchmatelrials include minerals, ores, coal, slimes,

trade wastes, water,v sewage, Wool grease, starch-glucose mixtures, etc., and concentrates, ymiddlings and tailings of former treatments of such materials.

The flotation apparatus herein disclosed bywvay oftexample comprises a series of combined pulpagltating and froth-separatmg cells or units located upon the same horizontalv level, each unit being providedwith a rotary propeller or pumping impeller, serving to agitate the pulp, andalso serving to `eti'ect a continuous positive flow of pulp through the apparatus.

The units are shown as havin intervened I vertical passages formed by the intermediate walls separatmg adjacent units, each pas sage comprisi g an up-flow conduit and a down-flow fc'on uit, each of said passages being provided with a Weir and being open to the'atmosphere at the top for the intrvoductionf of air. Instead of introducing air through the open top of a passage, any

gas other/ than air, mixtures of gas and air, i

reagents in the form of va or, orv smoke and air may be'introduc'e In this case `however, the top of the passage wouldbe closed to the atmosphere. ,Thetailin s residue from one unit may enter the rst or up-flow conduit leading to the next suc*-l ceeding unit, Iand cascade over the Weir into the second or down-flow conduit. Air 011-' f wei r slat structure.

tering through the open top of the passa e maybe entrained in the down-flowing pu p and the combined stream of pulp, air, etc., is then guided beneath, the impeller of the next succeeding unit, together with any reagents which may have been added through the open top of the passage. This impeller sucks the stream up into its unit for subjecting it to further agitation and permitting froth separation therein.

There is 'a practically unobstructed u ward movement of the air bubbles from t e zone of agitation to the froth layer and the bubbles laden 'with mineral are permitted to risel undiverted by any side current compelling means such, for example, as side currents of inflowing pulp or side movementcompelling guides or baies, so that the mineral laden bubbles from the zone of agitation may rise freely, unobstructedly, and quietly, carrying vtheir load of mineral u from unit to unit in a series of individua units or vessels in each of which the pul is agitated, line air bubbles are distribute into the f superincumbent froth layer. This .uY

is associated with a positive'feed of pul through it, and the air bubbles are permitted n to rise freel unobstructedly, and quietly into an over owing froth layer.

Among the ob]ects of the lnventlon are mcreased eflic1ency,1s1mpl1c1ty, economy and reliability. Other objects `and advantages will hereinafter appear.

y In the accompanying drawings is Ashown one form of apparatus embodymg our in vention: l

Figure 1- is a transverse sectional view 9 through the apparatus taken on the line 1 1 of Figure Figure 2 is a longitudinal sectional view taken on the line 2-2 of Figure 1, parts n being broken away. l Figure 3 is a top view partly in'section taken on the line 3 3 of Figure 2.l

Figurel is a sectional view of an alternative form of impeller and ad'acent parts.

Figure'ff is a plan view of t e same. 1

Figuref'G is a detail view showing the fg V The apparatus shown comprises a rectangular trough orbox having` a horizontal bottom` portion 1, two side walls, 2 and 3, 1

and two end walls 4 (only oneof which is ythe bottom of the apparatus.

shown herein), said vessel being divided into a series. of connected pulp-agitating and froth-separating cells or units, V5, 6 and 7. Any convenient number of units, -5, 6 and 7, may be arranged in series, but for convenience of description only two'complete units and a portion of a third have been illustrated.

At the feed' end of the apparatus, the left hand as viewed in Figure 2, a vertical wall 8 is provided, which with the end wall 4 forms a vertical feed conduit 9 extending to Converging members 10, which inc ne downwardly, constri'ct the bottom of the feed conduit 9 to form a funnel-shaped channel and guide the prepared pulp mixture into the narrow intake conduit or passage 11 extending under `the bottom member 12 of the first cell or unit 5. The intake conduit 11 terminates at its inner endin a semi-circle l13 concentric with the axis of the impeller to be hereinafter de- K scribed. The conduits 9 and 11 form a feed passage open to the air at the top down which the ulp is cascaded and through which it is rawn by the impeller of the first `unit to be hereafter described.

Each unit 5, 6\and 7 above referred to includes a transverse wall 8, a bottom member 12 having a centrally located inlet 13a; a

.transverse wall 14 having a horizontally elongated rectangular outlet 15, and side walls 2 and 3. In each of said units there is provided a rotating vertical spindle 16` suitably supported in overhead bearings17 and 18 and carrying at its lower end avrotary impeller 19 having a suitable number of inclined blades 20, four in this instance.v Instead of employing inclined impeller blades, any other suitable type may be used. The axis of the impeller 19 is located directly above the circular opening 13 in the bottom 12 of the unit, said opening being concentric with the semi-circle 13, but considerably smaller. The spindles 16.may be driven in any suitable manner, as by a 'shaft 21 connected thereto by suitable gearing (not shown) in the housing 22. Other types of impellers may also be used instead of the ordinary cross-arm agitator shown in Figures 1 to 3. A J

Figures 4:V and 5 show a second forni of impeller comprising an upper disc 56 and a lower disc 57 and between them inclined webs or blades 58 extendingoutto the full Ldiameter of .the lower disc and beyond the outer ,diameter of the upper disc so that parts of their edges are exposed.l These webs or blades 58 terminate at their inner ends at a substantial distancefrom the axis of theimpeller, leaving la central chamber 59. 'The lower disc 57 has an opening 60 u which the pulp may flow into the central c amber for distribution between the webs or"blade`s."""As-'shown, an fair. pipe 6l eX- tends up into the chamber 59 so as to discharge air therein, but this pipe may be omitted if sufficient air is otherwise supplied.

The outlet 15 may be made suiiciently small to cause the tailingsv to flow therethrough at a velocity high enough to prevent clogging up of the passages of the apparatus due to settling of large or heavy v particles.

l For preventing the walls ofthe cells in `the zone of greatest agitation from wearing out, due to the abrasive action of the pulp, lining members or liners, 23, 24, and 26, may be employed, preferably extending from the cell bottom to a point just below the'outlet 15. These liners and also the cell bottom may be made of any suitable wear resistant material, such as cast-iron orhardwood.

Any suitable baffling means for quieting the motion of the pulp may be interposed between the impeller blades 20 and the outlet 15. The baiile herein disclosed, which may also be made of cast-iron, gomprises four` diagonally arranged vertical crosspieces 27, radiating from an inner'square boxing 28'surrounding and spaced from the spindle 16. Each of the cross-piecesf27 has upon its outer enda triangular anchor member 29; and the cross-pieces and the triangular members areattached. by screws, or the like, to the lining at the corners fof, the cells.

The feed or material to be treated in the apparatus may first be prepared in a preliminary mixer, as, for instance, a chamber to the open conduit leading to any cell of 1 the series. The material orpulp thus prepared may then be fed through the feed pipe 30 into the vertical feed conduit 9, l from which it flows into the horizontal intake conduit 11 leading to the center of the first cell or unit 5 from which it isdrawn up into that cell'or unit by thepumping *c action of the inclined blades 20 of the rotary impeller l19 located therein. The impeller blades thoroughly agitate the pulp-and-air stream delivered thereto, forming bubbles and causing the stream to rise with a rapid swirling motion. The rising swirling stream of bubbles" and pulp is quieted bythe baffle, and the concentrate-carrying bubbles iow upwardly to the4 surface of the l"vertical passage leading to the next vsucceeding unit.

The vertical passages connecting the adjacent units of the apparatus arev each divis vided into two portions by a dividing wall including a partition.36,'thus forming an upow conduit 34 and a downflow conduit 35. A l

The upflow conduit 34 extends from the outlet 15 to the top of said dividing wall, while the downflowconduit 35 extends from the top of said wall lto the bottom ofthe,

intake conduit 11 leading into the next cell. The dividing 'wall of said passage comprises a. short lower vertical partition 36 above which is located a central guiding and Spacing member 37 vseparating the two adjustable weirs 39 and 47 located on either side thereof. A vertical partition 38 divides the uplow passage into two parts so that the pulp enters the downow passage in two streams, one from each of the weirs. The Weir adjacent the wall 2 of the cell comprises a sheet metal plate 39, preferably of cast iron, sliding in grooves 40 and 41 vformed in the dividing member 38, and the guide 38, respectively. The metal plate 39 is provided with an upwardly extending adjusting rod 42 threaded at its upper end and passing through an opening in the metal supporting plate 43 mounted upon the cross beam 44where it is engaged and` may be raised or lowered by the threaded hand-wheel 45. To prevent leakage of pulp around the edges of said metal weir or gate, suitable rubber strips may be located in said Agrooves 40V and 41.

The weir or gate adjacent the Wall 3 of the cell consists of a series of superposed removableslats 47, said slats extending into the guideway 48 formed by the member 38,

. and the upright members 49 and 50 and also tangularngroove in the guide 51.

cxtendinfr into the opposing rabbeted -rec- -l'al outlet slot 15 into the vertical uplow conduit 34, and cascades overv bothof the level controlling weirs 39 and 47, and plunges into the downlow condu1t 35 ,fro m which it flows into the intake passage 11 of the unit 6. l

The action ofthe pulp in the downflow l conduit 35 is precisely similar to its action in the feed conduit 9, already described. Thus the cascading pulp stream entrainel air which enters through the open top of thel conduit and together with any supplementall dotation or other agents which may be added at this time, falls and splashes through the funnel-shaped channel formed by the inclined portions 10 of said downflow conduit and surges through the horizontal conduit 11 and isrdrawn up into the agitation zone of the `nextcell by the pumping action of the i'mpeller located therein.

In order to rintroduce the proper amount of air to eiliciently aerxte the pulp, the factors controlling theopeiatioirmay be so adk/justed hat the impellers tend to ldraw in pulp fa ter than it is beingsupplied through the conduits, so-that the downlow conduits are not allowed to flow full, but free airA is sucked in with the streams of pulp. l

The double-passages with the adjustable weirs therein connecting the cells thus serve notl only to control the level of the pulp in the cells and topermit the addition of flotation and `other agents into each cell, but the conduits alsov make possible the Aai-itomatic introduction of air into each individual cell for aerating the pulp, without the necessity for employlng the expensive air compressors common in previous flotation apparatus.

The froth, after owing over the lips 31 may all be combined into a single stream and collected in either one of the troughs 32a or 33 of the commondouble launder 32.

It may be found desirable in some cases to separate the froth of the first cells from the froth of the last cells of the series, so that the latter may be returned to -the circuit for further concentration. To effect such a separation, hinged aprons 52, which may be pivoted to the centralwall of the common 1 to` the positions indicated by dotted lines. This permits vconcentrates to be drawn oil through the trough 32'i While the middllngs fromv the last cells are combined in the trough 32 and returned to the circuit at any desired point.

As will be noted, this apparatus effects a positive delivery vof all of the tailings residue from cach unit through the open conduit into the next ,succeeding unit. This insures that all the tailings flowing from each unit are reagitated andreaerated in the next unit ofthe series, even when all the units are located on the same horizontal level. Each cell'oic the series thus comprises a combmed agitating and separating vessel havin means for automatically sucking 1n an' from the atmosphere,- thus. usually malrng`- untheV froth depth, the froth discharge area,

' from lthe upflow conduitto the, downflow necessary the use of spitzkastens or air compressors. I v l 4 The proportions and nature of agents employed, the pulp density, the peripheral speed of impellers, the speed o-f pulp flow,

and other factors will vary greatly with different ores and other materials to be treated. Before utilizing thisapparatus for the concentration of any particular ore' or other material, therefore, a simple preliminary test mav be necessary to determine the conditions which will/yield the character anddproportions*offrothE and tailings des1re y It is found that froth paddles are. usually unnecessary to secure sufliciently rapid remolval of the froth fromithe surface of the 1f it -isdesired, when treatingsome materials, to introduce an additional amount of air to one or more of the cells, a plug 53, preferably ofwood, may be removed from an opening 54 in the bottom of the apparatus, and an air pipe inserted. Such an air pipe is shown in Figure 4, combined with an alternative form of impeller'.

When operating `on pulps carrying heavy 'sands or large particles, it may be desirable in some instances to provide a by-pass such as the orificev v55 in the partition 36, to allow a portion of the pulp containing the heavy or large particles 'of said pulp to flow directly conduit, thus avoiding the lnecessityof carrying said particles over the Weir and also preventin any obstruction due to settling in the up ow conduit. This orifice `55 may be conveniently located opposite the rectangular outlet 15. Ordinarily, however,

this orifice will be closed bythe plug, as\

shown.

The' general principles of the invention embodied in the foregoing specific apparatus may be applied in other forms of apparatus lb y the exercise of the technicalF skill of the art and still other adaptations may be inventlvely devised,` all within the scope of the following claims:

Te claim: f' 1. In a froth-flotation separation apparatus a combined agitating, gasifying and froth-separating chamber, an^ inlet passage provided with means for cascading the pulp 'therein' and having an inlet entering the chamber inthe bottom wall of the chamber, a baille vin the chamber, an agitator at the lower part of the chamber above the inlet, and below the baftleand arranged toexert suction on -the pulp to fdraw the pulp upwardly through the inlet and force the pulp upwardly past the baille through the chamber, the chamber being unobstructed except for the baille therein above the agitator so that the bubbles may rise directly upward ing froth layer'. above the pulp, andan outlet for thev pulp leading outfrom the chanberat a substantial distance below the pulp level therein.

2. An apparatus for froth-flotation separa` tion comprising a plurality of'units, each of which units is both a pulp-agitating and a froth-separating chamber rovided with apulp inlet and a tailings outlet, the pulp inlet in each unit entering the bottom wall of the chamber and thetailings outlet in each unitv being a substantial distance below the pulp level in the chamb'er, the tailings outlet and the pulp inlet of units in series being connected by a a passage provided with` a Weir overflow for controlling vthe level of the pulp in the preceding unit and` with means lfor cascading the pulp therein and flowing the same substantially horizontally. to the pulp inlet of the next unit in series, each\ofv which chambers is provided with a baliie and with an agitator at thelower part'of the chamber above' the .inlet and' below the bathe and arranged to exert 'suction on the pul to vdraw'gthe pulp upwardly through the inlet and" force the pulp upwardly astthe baille and through the chamber, t e chamberl bein unobstructed except for the baille therein above the agitator so that the bubbles may rise upwardl from the zone of agitation tov an overflowing froth vlayer above the pulp.

-tion comprising a plurality of units, each vof which units is botha pulp-agitating and a froth-separating 'chamber and is provided 3. An apparatus for froth-flotation separa-A with a pulp inlet and a tailings outlet,y the tailings outlet and pulp inlet of each two adjacent units being connected by a passage provided with an adjustable weir overflow pfor controlling the y'level of the pulp in the preceding unit, and each f'which units is provided with an agitator at the lower part of the chamber above the' inlet, and a baflfle above the agitator. for directing the pulp upwardV from the zone of agitation, said chamber being unobstructed except for the baie above the agitator so that the bubbles may rises` directly upward from the zone of agitation to an overflowing froth layerabove the pulp. A

`4. An apparatus for froth-flotation separation comprising a plurality of'units, each of which units is both a ulp-agitating and a froth-separating chamber 4and is provided with a pulp inlet and a. tailings outletth'e l tailings outlet and pulp inlet of each two adjacent units being connected by a passage of suehwidth as tov provide a 'gas space above the pulp therein, andl each of which units is yprovided with an agitator at the lower part of the chan'lberr above the inlet adapted to act ,as a pump to draw pulp up into the chamber, and a bale above the agitator for directing the pulp upward from lthe zone of agitation, said chamber being unobstructed except for the baille above the agitator so that the bubbles may rise directly upward from the zone of agitation to an overowin'g froth layer above the pulp.

5. An apparatus for froth-flotation separation' comprising a unitary pulp-agitating and froth-separating chamber, 'means :for admitting gas and pulp to the bottoni of the chamber, an agitator in the chamber capable of drawing in air and pulp through said means against substantially, the head of pulp in the chamber a baille above 4the agitatorJ for directing the` pulp upward from the zone of agitation, a froth-separating lip, a pul exit of considerable width below the frot level, and a conduit leading upward from the exit and having means therein for controlling the level of the pulp in the chamber.

6. An apparatus for froth-flotation separation comprising a unitary pulp-agitating and froth-separating chamber, means for admitting 'gas and pulp tol the bottom of the chamber, an agitator in the chamber ca able of drawing in air and ul against su stantially the head of pulp in't e chamber, a baille above the a 'tator for directing the pulp upward from t e zone of agitation, a lfroth-separating lip,a pulp exit of con.-

. siderable width below the froth level, and

a conduit leading upward from the exit and having a weir overflowV forr controlling the level of the pul in the chamber.

7. An apparatus' or froth-notation sep- ?aiation com risiii' a unita ul -a "tating P g. Igel P g1 and froth-separating -chain er, means for admitting gas`- 4o. in the cham er, means for admitting gas';

r, lan agitator in the ,cham and pulp to the bottom of the chamber, an agitator inthe chamberv capable of drawing in air and pulp against substantially .the head of pulp in the chamber, a= baie above the. agitator for directing the pulp upward from the zone of agitation, a froth` separating lip, a pulp exitof considerable width below'the froth level, and a conduit leading upward from the exit and havin'g an ad]ustable weir overflow for controlling the level of the pul in the chamber., I 8. An apparatus or froth-flotation'separation comprisin a unitary pulp-agitating and froth-separating chamber, `a suction agitator in the. chamber, means for admitting gas and pulp to the chamber beneath the agitator a froth-separating lip, a pulp exit below the froth level, a conduit leading from the exit, a weir overilow'from sai conduit, a second 'froth-se arating chamber and a conduit' for conveying the tailings of the i'st chamber to the second chamber extending from-'the Weir overflow o f the first chamberN and having a drop therein adapted- 9. .An apparatus for froth-flotation separation comprising a unitary pulp-agitating and froth-se arating chamber, an agitator in the chamber, means for admitting gas and pulp to the chamber, a froth-separating lip, a pulp exit below the froth level, a conduit leading from the exit, a weir overflow from saidmconduit, a second pulp-a itatingI and froth-separating chamber, a con uit for conveying t e tailings yof the'frst chamber beneath the ysecond chamber extending from the weir overflow ofF the first chamber lip, a pulp exit belowthe froth leve a con-v duit leading from theQ exit, a Weir overow rom\said conduit, a second pulp-agitating and froth-se arating chamber, a conduit for conveying t e tailings of the -irst chamber to the, second chamber extending from the weir overfiow'of thefirst chamber and having means for entry of air therein and of such rwidth as to provide a gas space aboveA the pulp, and an agitator in the second er, me ns for admitting gas v chamber adapted to pump the tailin s from y said tailings conduit, together wit addi'- ltional gas from said' gas space, into the second chamber. f

11. An apparatus -for frothflotation Separation comprising a unitar pulp-agitating and froth- Aarating 'cham er, an agitator and pulp to the chamber, a. frothparating llip, a pulp exit below the froth leve a conduit leading fromth'e exit, a weir overflow from said conduit, a second pulp-a tating lll and froth-se arating chambeiya con uit for conveying t e tailingsv ofthe first chamber to the second chambenextending from the weir overflow of the irst'chamber, and hav: ing means for entry of gas therein, and having a drop therein adapted to cause the entrainment of gas, and of. such width as to` provide a gas space above the pul and an agitator in the second chamber a apted to sump the t ilings from said tailings conuit, together with additional gas from 'said gas space, into the second chamber.r f

12. ,An apparatus for froth-flotation separation comprising a unitary pulp-agitating and froth-separating chamber, meansffor admitting gas`and pulp to the chamber,` a A froth-'separating lip,'a pulp exitbelow the froth level, a conduit leading from the exit, and/ a Weir-,overflow from said conduit comprising integral lpieces removable for ad- Justing the height of the weir and also com-y v prisin a Weir gate adjustable upand down to fine y adjust thelevel of the pulp in the v fchamber.

v13. In an apparatus` for froth-flotation separation, a series of unitary vessels in ichthe material isjagitated and aerated and,` the froth is separated, a vpassage connectin lthe outlet of one of* said vessels with the i et of another, said passage having vertical walls and including a fixed interior artition dividing said passage into an u'pow `conduit 'and a downow conduit;v an

outlet leading into said upilow conduit, an

inlet leading from the bottom of said down# flow conduit, and an adjustable .Weir above said partition, said Weir comprising two sections, one of said sections includinga series of removable slats resting upon said pari tition and the other section including'a gate supported in sliding'contact with said parti- 20` l tion, and means to adjustably support saidj

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